I known interfacelift for 2 years now, and i never ceased to be amazed by the quality of the photographs people posted on interfacelift
Here are some of my favourite wallpaper collection from them. It matches with Windows 7 pretty well and i tried it with Rainmeter’s enigma theme.
Unfortunately i only had them in 1680×1050 reso. Head down to interfacelift for more pictures and other resolutions, including full HD and above.